An Employer Identification Number looks like a nine-digit number split by a single hyphen after the second digit, in the pattern XX-XXXXXXX. A real example would read 12-3456789. That two-then-seven arrangement is the format the IRS uses for every EIN it has ever issued, and it is the quickest way to tell an EIN apart from other tax identification numbers at a glance.1Internal Revenue Service. About Form SS-4, Application for Employer Identification Number (EIN)
The Two-Seven Format Explained
Every EIN is exactly nine digits long, always displayed as two digits, a hyphen, then seven digits. There are no variations. No EIN is longer or shorter, and the hyphen never appears in a different position. The IRS is authorized under federal law to issue these identifying numbers to any person or entity required to file tax returns or other tax documents, and the format has stayed consistent across every number assigned.2Office of the Law Revision Counsel. 26 USC 6109 – Identifying Numbers
When you see the number written out in official correspondence, it will typically include the hyphen. Some databases and forms strip the hyphen and show all nine digits together, but the underlying structure is the same: the first two digits are treated as a prefix, and the remaining seven identify the specific entity.
What the First Two Digits Tell You
The two digits before the hyphen are called the prefix. Years ago, the prefix told you which IRS district office had processed the application. The IRS has since centralized its operations, so the prefix no longer points to a geographic location. Today it identifies which IRS campus assigned the number, or whether the number was assigned through the online application system.3Internal Revenue Service. Part 2. Information Technology – 2.4.8 Command Codes ESIGN and BSIGN
For example, prefixes 10 and 12 are associated with the Andover campus, while prefixes such as 20, 26, and 27 indicate the EIN was issued through the IRS online application.4Internal Revenue Service. Valid EINs The prefix does not tell you anything about the type of business, its size, or where it operates. It only reflects how and where the number was originally assigned.
How an EIN Looks Compared to an SSN or ITIN
Several federal tax identification numbers are nine digits long, so the hyphen placement is what separates them on paper. A Social Security Number uses a three-two-four pattern, written as XXX-XX-XXXX. An Individual Taxpayer Identification Number uses that same SSN-style format but always begins with the digit 9.5Internal Revenue Service. Taxpayer Identification Numbers (TIN)
An EIN’s two-seven split is visually distinct from both. If you are looking at a nine-digit number and the hyphen sits after the second digit, it is an EIN. If the hyphen sits after the third digit, it is either an SSN or an ITIN. That single visual cue is reliable across every form and document the IRS produces.
Where You’ll See Your EIN in Writing
The clearest place an EIN appears is on the CP 575 notice, the confirmation letter the IRS sends after approving an application. This is a one-time document that displays the newly assigned number along with the tax forms the entity will be required to file. Applicants who applied online can download the notice immediately; applicants who applied by mail or fax receive it in the mail.
After that first notice, the number shows up in several predictable places:
- Federal tax returns filed by the business, such as Form 1120 for corporations or Form 1065 for partnerships.6Internal Revenue Service. Instructions for Form 1120 – U.S. Corporation Income Tax Return (2025)
- Form W-9, which clients and vendors use to collect a taxpayer identification number before reporting payments made to a business.7Internal Revenue Service. About Form W-9, Request for Taxpayer Identification Number and Certification
- Bank and financial institution records from the account opening.
- Payroll reports and other routine business correspondence.
In every one of those places, the number will follow the same two-seven format. If you spot a nine-digit figure at the top of a business tax return with a hyphen after the second digit, that is the EIN.
Retrieving the Number If You Can’t Find It
If you know what an EIN looks like but cannot locate your own, the IRS suggests a few places to check first. The original CP 575 notice is the primary record. A previously filed federal tax return will display the number near the top of the form. Your bank will have it on file from when the business account was opened. State or local licensing agencies where you registered the business may also have it in their records.
When none of those turn up the number, you can call the IRS Business and Specialty Tax Line at 800-829-4933, Monday through Friday, 7 a.m. to 7 p.m. local time. After verifying your identity, the IRS will provide the number over the phone, and you can also request Letter 147C, a written confirmation of your previously assigned EIN.8Internal Revenue Service. Employer Identification Number Letter 147C is useful when a bank, lender, or contracting partner wants written proof of the number and you no longer have the original CP 575.
The number itself never changes shape on any of these documents. Whether it appears on a CP 575, a Letter 147C, a 1099, or a bank statement, an EIN will always be nine digits, always carry a hyphen after the second digit, and always identify the same entity for the length of its existence.